#include <iostream>
#include <list>
using namespace std;

int main(int argc, char const *argv[])
{
    list<char> coll;
    for (char c = 'a'; c <= 'z'; c++)
    {
        coll.push_back(c);
    }

    while (!coll.empty())
    {
        cout << coll.front() << ' ';
        coll.pop_front();
    }
    
    cout << endl;
    
    return 0;
}
